This invention relates to the continuous production of polymeric foam slabs or buns, as they are commonly referred to in the art, and more particularly to an expansible trough and fall plate for use in such production by which the width of the forming bun can be varied to a desired length.
A method and related apparatus for producing continuous foam buns in which the trough and fall plate of the present invention to be used are disclsoed in United States Letters Pat. Nos. 3,786,122 and 3,832,099, which patents and all of the teachings therein are hereby incorporated by reference. Essentially, the method taught in those patents for continuously producing polymeric foam buns, or strands as they are referred to therein, comprises the steps of continuously supplying a mixture of liquid foam reactants to the bottom of a rigid vessel or trough, allowing the mixture to expand upwardly and foam in the vessel due to the chemical reaction between the reactants and, prior to the completion of this expansion, allowing the partially expanded foam to flow upwardly from the trough over a weir structure, down an inclined fall plate and onto a channel shaped conveyor in which the foam is continuously drawn away from the structure. As the foam expands and rises in the trough and passes over the weir, it changes from a generally liquid state to a generally solid state and on the conveyor solidifies into a generally flat bun of polyurethane foam.
While the aforesaid process has been found to be an improvement over the previous methods used for forming such buns, the improved process nevertheless had certain shortcomings. Most notably, the bun of polymeric foam produced by the process was always of the same width. If differently sized buns were desired, it was necessary to saw the bun to the desired width which not only consumed additional time and expense but often resulted in a waste of product. In addition, the vessel or trough in which the mixed chemicals are received was extremely difficult to clean after a run of a particular material due to the nature of the material involved, thereby further increasing the overall costs of production. It would be highly desirable to provide equipment which could be used in such a process which would be capable of producing buns of polymeric foam of different desired widths and which would alleviate the problem of cleaning heretofore experienced with the apparatus used in the process.